Expeditions

Pitcairn Islands

At Sea: March to April 2012Country: United Kingdom

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The Place

In 1789 the H.M.S. Bounty mutineers, evading British justice, set off from Tahiti in search of a refuge. What they found was one of the most remote islands on Earth, located thousands of kilometers from any continent. In an act that sealed their fates, the group sank the Bounty off the island’s coast—and remained there, undiscovered, for 18 years.

Today the Pitcairn Islands are among the last of the British Overseas Territories, and Pitcairn itself is home to fewer than 60 people. Many are the direct descendants of the Bounty’s Fletcher Christian, his fellow mutineers, and their Polynesian companions. They are the only inhabitants of an archipelago of four far-flung islands and atolls. These include Ducie, the world’s southernmost atoll and one of the most remote on the planet; Henderson, a raised coral bed topped with rugged greenery; and Oeno, the closest of the islands to populated neighbor French Polynesia.

Due to their remoteness and low human population, these islands harbor marine wildlife in an almost pristine state, including intact deep-sea habitats with many species new to science.

Map by NGS Staff; Charles Preppernau

The Mission

In March 2012, Pristine Seas, in cooperation with the PEW Charitable Trusts, undertook a month-long expedition to determine the health of the marine environment surrounding the four Pitcairn Islands. Over the course of the expedition, the team of top marine ecologists and filmmakers made 384 dives, spent more than 450 person-hours underwater, and counted and measured thousands of species of fish, coral, and algae. What they found were exquisite and highly functional ecosystems, beginning with that of remote Ducie atoll.

In the waters surrounding Ducie, located 500 kilometers east of Pitcairn, sharks such as gray reefs and whitetips were abundant, accounting for 65 percent of the fish biomass (or total weight)—the ultimate sign of a healthy reef. Live corals covered up to 100 percent of the seafloor, and divers experienced visibility up to 75 meters, the clearest ever measured in the Pacific. The waters off Henderson Island were nearly equally healthy, home to top predators and the Napoleon wrasse, largely depleted in shallow reefs elsewhere.

At Oeno atoll, the team found up to nine giant clams per square meter, and schools of barracuda joined other predators such as the yellow-edged lyretail. But sharks appeared to be entirely absent, likely a result of fishing activity due to the atoll’s relative accessibility. Off the island of Pitcairn itself, divers found healthy corals, an abundance of fish, and even a previously unreported deep coral reef—but no sharks.

The team also conducted deep-sea explorations of 40 Mile Reef, the deepest well-developed coral reef known to man. Using drop-cam technology, researchers found 57 species of fish—eight of which were new to science. Meanwhile, expedition conservationist Mike Fay walked the surface of the islands, recording plant and bird life, as well as signs of human impact, including a centuries-old shipwreck, modern ocean-borne plastic trash, and the persistent presence of accidentally introduced rats.

Species never before reported at Pitcairn included those of algae, corals, reef fishes, and rare deep-sea sharks. The expedition even revealed the world’s deepest known living plant, a species of encrusting coralline alga found at 382 meters.

The Result

Following the expedition, the Pristine Seas team worked with the Pitcairn Island Council and Pew to draft a proposal for a no-take marine reserve that would cover the islands’ entire exclusive economic zone. The community voted unanimously in favor of creating the reserve, and in March 2015, the British government established the Pitcairn Islands Marine Reserve. At 834,334 square kilometers, it’s among the world’s largest ocean reserves.

No fishing or seafloor mining is allowed in the reserve, with the exception of traditional fishing around the island of Pitcairn by the local population.